On Thu, 13 Jun 2019 19:49:40 +0200, Brian Norris wrote: > > Hi Takashi, > > On Wed, May 29, 2019 at 02:52:20PM +0200, Takashi Iwai wrote: > > Currently mwifiex_update_bss_desc_with_ie() implicitly assumes that > > the source descriptor entries contain the enough size for each type > > and performs copying without checking the source size. This may lead > > to read over boundary. > > > > Fix this by putting the source size check in appropriate places. > > > > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> > > --- > > drivers/net/wireless/marvell/mwifiex/scan.c | 15 +++++++++++++++ > > 1 file changed, 15 insertions(+) > > > > diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c > > index 64ab6fe78c0d..c269a0de9413 100644 > > --- a/drivers/net/wireless/marvell/mwifiex/scan.c > > +++ b/drivers/net/wireless/marvell/mwifiex/scan.c > > @@ -1269,6 +1269,8 @@ int mwifiex_update_bss_desc_with_ie(struct mwifiex_adapter *adapter, > > break; > > > > case WLAN_EID_FH_PARAMS: > > + if (element_len + 2 < sizeof(*fh_param_set)) > > "element_len + 2" would be much more readable as "total_ie_len". (Same for > several other usages in this patch.) I can send such a patch myself as a > follow-up I suppose. Yes, please. > > + return -EINVAL; > > fh_param_set = > > (struct ieee_types_fh_param_set *) current_ptr; > > memcpy(&bss_entry->phy_param_set.fh_param_set, > > [...] > > > @@ -1349,6 +1361,9 @@ int mwifiex_update_bss_desc_with_ie(struct mwifiex_adapter *adapter, > > break; > > > > case WLAN_EID_VENDOR_SPECIFIC: > > + if (element_len + 2 < sizeof(vendor_ie->vend_hdr)) > > Why 'sizeof(vendor_ie->vend_hdr)'? The (mwifiex-specific compare with the > ieee80211.h generic struct ieee80211_vendor_ie) ieee_types_vendor_header struct > includes the 'oui_subtype' and 'version' fields, which are not standard > requirements for the vendor header (in fact, even the 4th byte of the > OUI -- "oui_type" -- doesn't appear to be in the 802.11 specification). > So it looks to me like you might be rejecting valid vendor headers (that > we should just be skipping) that might have vendor-specific content with > length 0 or 1 bytes. > > It seems like we should only be validating the standard pieces (e.g., up to the > length/OUI), and only after an appropriate OUI match, *then* validating the rest of > the vendor element (the pieces we'll use later). Hm, right, that looks too strict. Instead we need to check right before both memcmp()'s of OUI. thanks, Takashi
